Orientational phase transition in Na[sub [ital x]]C[sub 60] (1[lt][ital x][lt]3)

Journal Article · Mon Aug 30 04:00:00 EDT 1993 · Physical Review Letters; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.71.1383· OSTI ID:6265563

Yildirim, T; Fischer, J E; Harris, A B; Stephens, P W; Liu, D; Brard, L; Strongin, R M; Smith, III, A B ^[1]

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1. Department of Physics and Laboratory for Research on the Structure of Matter; University of Pennsylvania; Philadelphia; Pennsylvania 19104-6396 (United States) Materials Science Department and Laboratory for Research on the Structure of Matter; University of Pennsylvania; Philadelphia; Pennsylvania 19104-6272 (United States) Department of Physics; State University of New York; Stony Brook; New York 11794 (United States) SUNY X3 Beamline at the National Synchrotron Light Source; Upton; New York 11973 (United States) Chemistry Department and Laboratory for Research on the Structure of Matter; University of Pennsylvania; Philadelphia; Pennsylvania 19104-6323 (United States)

X-ray diffraction and calorimetry data on cubic Na[sub [ital x]]C[sub 60](1[lt][ital x][lt]3) reveal orientational ordering transitions at [ital T][sub [ital m]] above that of pure C[sub 60], e.g., [ital T][sub [ital m]]([ital x]=1.3)=325 K. The ordered phases are the same as in pure C[sub 60]: simple cubic, space group [ital Pa][bar 3], but the orientations in the disordered phase are more restricted. We explain how Na stabilizes the ordered phase to rather high [ital T], while K and Rb do not, in terms of Coulomb interactions between C[sub 60] molecules and and Na ions which we calculate from the local charge density of C[sub 60].

• DOE Contract Number: FG02-86ER45254; FG05-90ER75596; FG02-86ER45231; AC02-76CH00016
• OSTI ID: 6265563
• Journal Information: Physical Review Letters; (United States), Journal Name: Physical Review Letters; (United States) Vol. 71:9; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ALLOYS
CALORIMETRY
CARBON
COHERENT SCATTERING
COULOMB ENERGY
CRYSTAL DOPING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIFFRACTION
DOPED MATERIALS
ELEMENTS
ENERGY
FULLERENES
MATERIALS
NONMETALS
ORDER-DISORDER TRANSFORMATIONS
ORIENTATION
PHASE STABILITY
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SCATTERING
SODIUM ADDITIONS
SODIUM ALLOYS
STABILITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
X-RAY DIFFRACTION